Using a coffee grinder, to grind ordinary rice to make ground rice, this provides ground rice with effective gritty texture for this recipe. Melt the butter and sugar in a pan, allow to cool for a little while, then beat in an egg, and rice. In the pastry tart (blind baked), spread mincemeat, pour over the rice topping and bake for 15-20mins or until golden in gas mark 3/4.